Introduction to biological molecules

Question 1

Explain Ionic bonding?

Answer 1

Ionic bonding is the gain and loss of electrons between a metal and non-metal atom joining to have an increased stability

Ionic bonds are joined together by very weal electrostatic interactions, making them very double in water

Question 2

Why is maintaining the ion concentration critical?

Answer 2

Maintaining the ion concentration is critical as the cell must be able to maintain a balance of ion charge difference. If this is lost the cell can become turgid and burst or flaccid and die

Question 3

Give features of covalent bonds

Answer 3

Covalent bonds;

• Electrons are being shared
• Can be one from each atom or more
• Stronger than an ionic bond

Question 4

Give features of polar bonds?

Answer 4

Polar bonds;
- Not all electrons are shared equally which creates a slightly positive and negative side allowing for electrostatic interactions

Question 5

Give features of hydrogen bonding ?

Answer 5

Hydrogen bonding;
Hydrogen is slightly charged and attracted to molecules that are slightly negatively charged, creating a weak intermolecular force of attraction.

Question 6

Give features of Van Der Waals forces?

Answer 6

Vander waals forces;

• Very weak interaction
• Relatively transient (last for a short period of time)
• They determine how close individual atoms can get to one another, determining the overall 3D shape of a molecule
• The nucleus is surrounded by electrons that are constantly cycling, however they can have more electrons on one side than the other creating a negative charge. Causing neighbouring atoms to repel or attract.

Question 7

Give some intermolecular bonding?

Answer 7

• Disulphide bridge
• Hydrogen bonding
• Hydrophobic interactions

Question 8

What is the general structure for sugars?

Answer 8

(CH2O)n - 1 Carbon, 2 Hydrogen and 1 Oxygen

Question 9

What is the function of sugar within a cell?

Answer 9

Sugar is a source of energy for a cell

Question 10

Why can’t the same enzyme breakdown both glucose and galactose?

Answer 10

Enzymes can detect small differences in structures

Question 11

What is sugar a form of?

Answer 11

Sugar is a form of carbohydrate

Question 12

What is it called when 2 different sugars are joined together?

Answer 12

When 2 different sugars are joined together they are referred to as a Disaccharide molecule

Question 13

Why might sugars be joined together?

Answer 13

Sugars can be joined together in long chains for storage to be consumed later when sugar is required

Question 14

what are 1-2% of our muscles made. from?

Answer 14

1-2% of our muscles are made of glycogen for readily use of glucose

Question 15

what is 5-6% of the liver composed of?

Answer 15

5-6% of the liver is composed of glycogen, causing the body to have a high supply of glucose on standby if any muscles in the body suddenly require it

Question 16

What are fatty acids made from?

Answer 16

Fatty acids are made from hydrocarbon chains (A chain head and a long hydrogen and carbon tail)

Question 17

What kind of charge does the head of the hydrocarbon chain have?

Answer 17

The head of the hydro carbon chain as a negative charge because it is a carbide group (hydrophilic)

Question 18

How can fatty acids be stored?

Answer 18

Fatty acids can be stored as triacyl glycerol which can be used as a source of energy

Question 19

What can triacyl glycerol be broken down into and what can that substance be further broken down into as used for?

Answer 19

Triacyl glycerol can be broken down into fatty acids, which can then be broken down into acetyl coA which can be used in the citric acid cycle.

Fatty acids can also be broken down into glycerol which can be converted to make glucose and used to make energy through glycolysis.

Question 20

How are fatty acids used in cells?

Answer 20

Fatty acids are very important components of cell membranes, they can be linked onto a head chain act as the hydrophobic tail of a cell membrane. The hydrophobic and hydrophilic properties of these hydrocarbon chains allows the lipid bilayer membrane to be created

Question 21

What are the features of steroids?

Answer 21

Steroids;

• Are rich in carbon and hydrogen
• 4 fused carbon rings. with different functional groups attached
• Made in the body (e.g cholesterol - high cholesterol means that. there is too much of the steroid cholesterol) - statins are used to inhibit the pathways that synthesises steroids like cholestrol

Question 22

Draw an amino acid?

Answer 22

Amino acids have a core central carbon atom which on one side has an amino group (a nitrogen and some hydrogens, one hydrogen is positively charged making that functional group acidic) and on the other side they have a carboxyl group (carbon with one double bond to an oxygen and one single bond to an oxygen, making that group basic). They have an R-group which determines the type of amino acid.

Question 23

What can amino acids be polymerised together with?

Answer 23

Amino acids can be polymerised together via a peptide bond to make a protein

Question 24

Explain the chemistry behind a peptide bond?

Answer 24

In a peptide bond the negatively charged carboxide group of one amino acid reacts with the adjacent amino group of another amino acid where the carbon becomes joined to the
nitrogen.

Question 25

What are the 2 ends of amino acids that have been joined together called?

Answer 25

The end which has the free amino group is referred to as the N-Terminus and the end which has the free carboxide group is referred to as being the C-Terminus

Question 26

What are the 3 uses of amino acids?

Answer 26

Amino acids

• Sources of energy
• Neurotransmitters - E.g - Glutamic acid
• Precursors for other molecules (used to make other molecules).

E.g - Glycine is a precursor for porphyrin ring which is amino acids joined to an iron atom

Question 27

What is the structure of a Nucleotide ?

Answer 27

Nucleotides have a carbon - nitrogen ring (base) linked onto a five carbon sugar, where the sugar can be ribose (RNA) or Deoxyribose (DNA). It also has phosphate groups attached to the sugar (usually 3 and 1 is taken off to make ATP).

Question 28

What is the role of nucleotides?

Answer 28

Nucleotides are short term energy stores - ATP and GTP

Nucleotides can store electrons - NAD, NADP reducing store for biosynthesis of ATP reduction

Question 29

What is a cofactor?

Answer 29

A cofactor is a non-protein part of an enzyme that is required for biological activity of that enzyme, like a helper molecule.

E.g - Cyclic AMP is used in signalling to activate enzymes

Question 30

Give 2 examples of biomolecules that are hybrids?

Answer 30

Glycoprotein - Protein bound to lots of sugars

Glycolipid - A lipid bound to sugars

Question 31

What does the addition of sugars to biomolecules allow?

Answer 31

The addition of sugars can help stabilise the protein or lipid

Question 32

What is peptidoglycans and where are they found ?

Answer 32

Peptidoglycans are found in bacteria wall, have a short peptide chain and very long sugars.

Question 33

What are proteoglycans?

Answer 33

Proteoglycans are proteins from the extracellular matrix which have lots of sugars

Question 34

How does the structure of proteins influence immune response ?

Answer 34

• The difference between blood groups A, B and O is due to the different sugars that are present on lipids that are buried in the surface of the red blood cell.
• The outside coat of viruses are surrounded by loads of glycoproteins / sugars

Question 35

How do glycoproteins affect vaccines?

Answer 35

The sequence of sugars becomes an issue when giving vaccines as the Glycoproteins that are on the surface of the virus bind to the receptors in order to gain access to the human cell. Vaccinations try to block these interactions, however viruses can change the nature. of their sugar on the outside as they aren’t determined by genetic codes

Question 36

What can changes in amino acids result in?

Answer 36

A change in one amino acid can alter the receptors on an enzyme, meaning the protein cannot work properly as the binding site is not as robust

Question 37

What can changes in DNA lead to ?

Answer 37

Changes in DNA structures can prelude to mutations which can cause issues like cancers